Zindos and Mydoom.M work together. Mydoom.M laid out the path by infecting a large number of systems and preparing a list of them. Judging from the coding style the two worm were created by the same author, which further emphasizes the idea that this is a two-stage attack.

Zindos hitches a ride on the Mydoom.M highway. It uses the lists and the backdors, prepared by Mydoom.M, to quickly spread and hit its target, which is www.microsoft.com.